As one of the causes of the global warming phenomenon, the greenhouse effect caused by CO2 is pointed out, and countermeasures thereagainst have also been required internationally in order to protect the environment of earth. As generation sources of CO2, in the fields of activity of all the human beings that combust fossil fuels, the requirement for suppression of emission of CO2 tends to become stronger. Along with this, methods of bringing flue gas of boilers into contact with amine-based absorption liquids, such as aqueous amine compound solutions and removing and recovering CO2 in the flue gas have been energetically studied for, for example, power generation facilities, such as thermoelectric power plants that use a large quantity of fossil fuels.
In a case where CO2 is recovered from flue gas using such absorption liquids, amine compounds are entrained in CO2-removed flue gas from which CO2 has been recovered. Also, in order to prevent a situation in which air pollution caused by the amine compounds occurs, it is necessary to reduce the emission amount of the amine compounds emitted together with the CO2-removed flue gas.
In the related art, PTL 1 discloses providing a plurality of rinse sections that bring rinse water into gas-liquid contact with CO2-removed flue gas from which CO2 has been absorbed and removed by gas-liquid contact with an absorption liquid, thereby recovering amine compounds entrained in the CO2-removed flue gas, and sequentially performing recovery processing of amines entrained in the CO2-removed flue gas in the plurality of rinse sections. As the rinse water of this PTL 1, condensed water separated by condensing moisture contained in CO2 in the processing of removing CO2 from the amine-based absorption liquid that has absorbed CO2, and regenerating the amine-based absorption liquid is used.
Additionally, in the related art, PTL 2 discloses providing a cooling section that cools CO2-removed flue gas from which CO2 has been absorbed and removed by the gas-liquid contact with an absorption liquid, and a contacting section that brings condensed water condensed in the cooling section into countercurrent contact with the CO2-removed flue gas. Moreover, PTL 2 discloses providing a rinse section that brings rinse water into gas-liquid contact with the CO2-removed flue gas from which CO2 has been absorbed and removed by gas-liquid contact with the absorption liquid, thereby recovering amine compounds entrained in the CO2-removed flue gas, and condensed water that has been condensed in a cooling column that cools the flue gas before CO2 is recovered and is used as rinse water.